Alternating-current relay



No. 749.399. PATENTBD JAN. 12, 1904..

' G. w. PIGKARD. V

ALTERNATING CURRENT RELAY.

APPLICATION FILED AUG. 21, 1903.

.NO MODEL.

a M ATTORNEY.

No. 749,399. Patented January 12, 1904.

UNITED STATES PATENT OEEIcE.

' GREENLEAF IV. PICKARD, OE AMESBURY, MASSACHUSETTS, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

ALTERNATlNG-CURRENT RELAY.

SPECIFICATION forming part of Letters Patent No. 749,399, dated January 12, 1904. Application filed August 21, 1903. Serial No. 170,868. (No model.)

To a 107mm y 607L667? the above-mentioned disadvantages is the ob- Be itknown that LGREENLEAEIV. PICKARD, ject of this invention. 5 residing at Amesbury, in the county of Essex The invention, generically described, conand State of h lassachusetts, have invented cersists in a relay whose characteristic feature is tain Improvements in Alternating-Current an electromagnetic movement comprising a pivoted iron armature whose free end, adapted to form a movable pole, extends between the 5 5 two polar ends or pole-pieces of a core system, such ends being adapted to form fixed poles of a nearly-closed magnetic circuit of iron, and an electromagnetic helix or exciting-coil surrounding the said armature and one limb 60 of said core system, so that when energized by the passage through it of a current the 5 signals as an auxiliary to the telephonic part said coil operates to temporarily magnetize of the system, such call-signals virtually conthe said movable and fixed poles thus associ- Relays, of which the following is a specificaw l l stituting a third class of electrical communiated in its bore, (which is sufiiciently wide 5 tion.

The present invention relates to composite systems for the electrical transmission of in- 10 telligence, wherein telegraphic and telephonic communications may be simultaneously transmitted over the same main-line conductor or conductors, and has particular reference to the efficient and satisfactory transmission of callcations, which also at any time may occupy for the free lateral movement of the former the line conductor simultaneously with its use thercin,) with'like polarity, thus making them intelegraphictransmission. Ilheemployment reciprocally repellant, while the other limb of alternating currents for such signaling is of said core system being outside of said coil in practice highly desirable; but the provihas its polar end, which forms the said other 7 O sion of a call-receiving relay perfectly responfixed pole, at the same time temporarily magsive to an alternating current of frequency netized with opposite polarity, produced 2 5 sufficiently high to avoid interference with either by magnetic propagation through the the telegraphic part of the system and satisi substance of the core or in any ap n-opriate factory in all respects has been ditficult of atway, mutual attraction being thereby detainment. The call-receiving device heretoi veloped between said other fixed pole and the fore most generally employed in this associamovable pole, which latter beingrepelled by 3 tion has depended upon the partial opening l the fixed'pole of. the limb associated thereof or the establishment of a high resistance with within the exciting-coil and attracted by in a normally closed circuit, including a batthe said other fixed pole moves away from the tery, by the vibration of contacts placed in i former and nearer to the latter. the conductor of the said closed-battery cir- Limit-stops are mounted above the poles of 35 cuit. This arrangement is, however, not i the core system and armature, one of them, altogether free from objectionable features, that onthesideof the fixed pole associated with since it is liable under certain conditions of i thearmature-pole,beingnon-conducting,while 5 practice to give false signals due to the con- 1 the other on the outer fixed-pole side is concurrent transmission of the telegraphic curducting and serves as one of the contact-ter- 4 rent impulses and, moreover, involves the emminals of a controlled circuit, and a flat conployinent of a closed-circuit battery at each ducting-spring forming a continuation of the station. I armature and constituting the complementary 9 To provide a call receiving ap 'iaratus l contact-terminal of said controlled circuit expromptly and efi'ectually responsive to the 1 tends between said stops, resting against the 45 transmission of an alternating current of the non-conducting stop when the relay is unopdesired high frequency equally responsive erated and against the conductingstop to reversely to the cessation of such alternatingclose the said controlled circuit when the said current transmission and generally free from relay is excited and in operation. The resiliency of the said spring extension acts to slightly prolong the contact when the armature is retracted to its normal position.

vided for the armature to hold the same normally against the non-conducting or back stop and to restore the same thereto, when having ing or forward stop by the passage of an opcrating-current through the exciting-coil such current ceases to flow.

The relay thus constructed is of course operative with a steady current of single direction, but has been dey'ised with special reference to use in connection with an alternating current, and since with every alternation or reversal of direction of such current the two fixed poles and the movable pole all have their polarity simultaneously reversed it follows that there is no change of relation between them and that the armature-pole having been oscillated in the direction of the fixed pole of the outer portion of the core system by the first pulsation of current regardless of the direction will retain its deflected position and maintain the union of the contacts of the controlled circuit as long as the alternating current in the main circuit and excitingcoil continues and will only move back to its normal position nearer to the associated fixed pole, separating such contacts, on the cessation of such alternating energizing-current.

1n the drawings which accompany this specification, Figure 1 is a side elevation of the relay of this invention. Fig. 2 is a. vertical central cross-section thereof. Fig. 3 is a section of a detail on the line :r :1: of Fig. 2 looking toward the pivots and retractingspring of the armature and showing the arrangement of the latter and the lamination of the core system. Fig. 4 is a diagram of a composite system, wherein the relay of this invention is connected for operation as the principal factor of the call-signal-receiving apparatus of the telephonic portion of the system; and Fig. 5 illustrates a modification of the relay construction, wherein the necessarymagnetic polarity of the attracting fixed pole of the core system is imparted thereto by an individual magnetizing-coil.

R is the alternating-current relay.

K is the iron-core system.

(J is the electromagnetic helix or excitingcoil.

l) is the iron armature.

S is the fiat extension or continuation spring thereof.

P is the non-conducting limit-stop against which the said spring extension rests when the armature is in its normal or resting position. Q is the conducting limit-stop on which the said spring extension rests when the armature is in its operative position.

M M are the main-circuit binding-screws and are terminals of the exciting-coil.

F is a pin extending laterally from the armature at a point near the pivots thereof, and

I Ur a spring pressing upon the under side there- A maintaining and retracting spring is proof and tending to hold the said arn'iature steadily toward the non-conducting limit-stop P and acting to return the same thereto when 1 it has been deflected toward the conducting been oscillated into contact with the conduct 3 limit-stop Q.

The iron-core system K is preferably formed of laminated iron, as indicated atf in Fig. 3. the plates thereof being held together in any preferred way, as by bolts 7;, and may be mounted in slotted portions of brass baseplates 71 whose faces overlap and support the ends of the electromagnetic exciting-coil (I and whose ends turned at a right angle, as shown, may serve as feet 0 o for the relay.

One limb in. of the core s 'stem K passes through the bore of the exciting-coil and the other limb 11 passes outside or over the exterior of said coil and then at an angle across the end thereof, so that the two polar ends u and 1/ of the said limbs respectively are brought near to one another, the two limbs being united at their other ends to form a continuous core. The entire core is conveniently formed substantially as a. parallelogram, discontinuous at one corner, and constitutes a nearly-closed magnetic circuit, with closel v adjacent confronting polar ends a 1;, having a narrow magnetic-field space between them.

The magnetizing or exciting coil is adapted for connection in the main circuit by means of the binding-screws M and has a wide central bore for a purpose presently to be described.

The iron armature l) is pivoted or poised at one end by its trunnions Z, with adjustable screws mounted in suitable brackets near the heel end of the core K, and extends through the bore of the coil C parallel to and side by side with the core-limb 1/), being of such length as to bring its free end 1 into the space provided between the polar ends a and l; of the core. The purpose of having the bore of the coil C wide, as is now manifest, is to provide for the admission therein of the corelimb on and the armature l), which are thus both surrounded by said coil, and to afford suffieient space for the oscillation of the armature.

The limiting-stops l and Q, are mounted upon adjustable screws in opposite sides of the arched bracket V, and the armature extension-spring S, attached to the free end of said armature, passes between them and is ca pable of oscillating from each to the other.

Main-circuit conductors are represented by the wire ends shown as being attached to the binding-screws M, and the wires /I' of the controlled alarm circuit leading from the conducting limit-stop Q and the armature 1), respectively, are attached to the bindingscrews M If the coil 0 of this relay be connected in a circuit and a. current of a pro'1 )riate strei'igth passed through it, the polar end a of the corelimb m an'dthe free end y of'the armature D, associated with said limb and both encircled by said coil, will be temporarily-magnetized with definite and like and therefore mutuallyrepellant polarity, and thepolar, end 6 of the outer limb 12. of the core will at the same time be magnetized with an opposite polarity adapted to attract the armature. Under these conditions the said polar ends become fixed poles of the core system, while the free end of the armature is a movable pole sustaining a certain relation to said core'system. The armature or movable pole 3 repelled by fixed pole m and'attracted by fixed pole b, will swing toward the latter and will cause the springtongue S to separate from the resting-stop P and to establish contact with the conductingstop Q,-thus1closing the circuit of the conductors w. If now the direction of the main circuit be reversed, it is obvious that the polarities of the said fixed and movable poles will all also be reversed, so that if the armature and its associated fixed pole were in the former case 'magnetized with N polarity and'the other fixed pole with S polarity the steadily in such operative position as long as the said alternating current continues toflow and without regard to the frequent reversals thereof.

In the composite system of simultaneous "telegraphy and telephony represented by Fig.

4, L is the common line conductor, A and B the telegraph-stations, and H and I the tel-' and impedance-coils, and() O the terminal carth'conncctions. v I

The apparatus at the telephonic stations comprises the transmitting and receiving telephones symbolized by the' receivers T, the call-receiving appliances, the call-transmitting appliances, condensers c 0 interposed between the telephone-station instruments and 'theline conductor, suspension-switches v) 2:, controllingthe' alternative connection of the talking and signaling instruments, and keys or switches a a, controlling the alternativeconnection of signal-sending and signalrecciving instrun'icnts. At both telephonestations the telephone is shown at an unemployed moment, the receivers being on their hooks, andthecircuits of the telephone in struments branch from the main conductor at points 6 and 7 at stations H and 1.

Theapparatus is of the same kind at both normally by way of theback contact thereof to the coil 0 of the call-receiving 'or alternating-current relay R and to ground or return 0'. The said relay is thus in-the normal calling-circuit and controls the call-bell p, connected in the local circuit 20 of the battery j ln-practice the alternating-current relay B does not directly'closeandopen the local circuit 20 of said-bell, but controls the same through the medium of an interposed local circuit 18 and an intermediate relay R included therein. This is a-Well-known expedient, and its object is to prevent false signals due" to momentary contacts which may occasionally be established between the points Q, S of the-relay due' to undesired impulses or kicks from the telegra ihic side of the circuit.

The call-sending apparatus U is connected between the forward contact if of the key a and the earth in conductor 23.

It is necessary in such composite transmission as is described herein in order to opcrate through the condensers c to employ an alternating call-current, andit is also necessary for the avoidance of interference with the telegraphic relays to provide that the said current shall be of frequency as high as from one hundred and sixty to two hundred periods.

The key-being, as shown, in lts normal position, such a call-current transper second;

, thus energized and in turn brings its armature-eontact S into engagement with contactstop 9, thus closing the second local circuit 20 and operating the call-signal bell n, which will continue to ring as long as the distant key is depressed.

To send the call-signal from station H, the key n is operated, temporarily disconnecting the relay branch and substituting the alternating-current generator U.

Alternating currents of the frequency required may readily be developed by any convenient and suitable source or apparatus, and although a dynamo-electric generator is indicated any such recognized equivalent, as a battery associated with an induction-coil and vibratory circuit-breaker, may of course, if desired, be employed.

The modification illustrated by Fig. 5 concerns merely the mode of effecting the magnetization of the outer fixed pole b of the relay R and shows the limb a of said core as being provided with an exciting-coil W of its own connected in series with the principal coil C and in such manner as to insure the opposed polarity of the fixed pole b. In cases where this modified construction is adopted it is of course not essential that the core shall be continuous from one pole to the other, and, if desired, the uniting-heel of the core may without change in the character of the operation be dispensed with, so that the two limbs are quite separate. The only requisite is that their active poles a and b shall be of opposite character or sign.

Having thus fully described the invention,

its mode of operation, and one application thereof, I claim 1. The hereinbefore-described electromagnetic movement, consisting in an iron-core system having two fixed and confronting polepieces; a pivoted iron armature with its free end extending between the said fixed polepieces, and itself constituting a movable polepiece; and a magnetizing helix surrounding the said movable pole-piece and one of the said fixed pole-pieces, and adapted when energized by the passage of an electric current therethrough to develop temporary magnetism of like polarity and consequent mutual repulsion between the said coil-surrounded fixed and movable poles, and opposite temporary polarity in the other fixed pole-piece, and consequent attraction between the same and the said movable pole piece as long as the said passage of current continues, and without regard to its direction.

2. A relay adapted to respond by the steady attraction of its armature to its operative position to a high-frequency alternating-current, comprising a magnetizing or exciting helix; a soft-iron-core system having fixed and movable pole-pieces surrounded by said coil, and a second fixed pole piece extraneous to said coil; and means for establishing temporary magnetic polarity in said second fixed polepiece opposite in sign to that established by said coil in the said fixed and movable polepieces surrounded thereby; the said movable pole-piece being mounted between the two fixed pole-pieces, and the bore of said coil being sufficiently large to permit of the lateral movement therein of said movable pole-piece; whereby when the said coil is excited by an alternating current, like temporary polarity is developed in said coil-surrounded fixed and movable pole-pieces, and opposite temporary polarity in the said other fixed pole-piece; and whereby the polarity of all of the said polepieces is simultaneously reversed at each reversal of said current; substantially as described.

3. A relay, comprising a soft-iron-core system having two fixed and confronting polepieces; a soft-iron armature pivoted or poised at one end and having its free end extending into the space between said pole-pieces, and constituting a movable pole-piece organized to oscillate between said fixed poles; an exciting -helix surrounding the said movable pole-piece and one of the said fixed pole-pieces, in electromagnetic inductive relation to all of the said pole-pieces, and adapted when energized to develop like magnetic polarity in the fixed and movable pole-pieces thus associated therein, and opposite polarity in the other fixed pole-piece; a maintainingand retracting spring for the said armature; and electrical contacts controlled by said armature; substantially as and for the purposes set forth.

L. A relay comprising an exciting or magnetizing coil; an iron core extending through the bore and back over the exterior of said coil and forming a nearly-complete magnetic circuit, with closely-confronting poles at one end of said coil; a soft-iron armature extending through said coil, pivoted or poised at one end to oscillate laterally therein and having its free end between said poles; a counter spring for the said armature; a contact-spring carried by the free end of said armature; and limiting-stops for said contact-spring, one of said stops being an electrical contact-point; substantially as set forth.

5. An alternating-current relay operating by magnetic repulsion and attraction and consisting of an iron-core system composed of two limbs united at one end and having their other ends approximated to constitute a nearlyclosed magnetic circuit with closely-adjacent confronting polar ends; an iron armature pivoted or poised near the heel ends of said corelimbs, extending forward in close association with one of them, and having its free end in the field-space between the polar ends of both; an electromagnetic coil or helix surrounding the said armature and its associated core-limb and adapted when energized by the passage of an alternating current therethrough to develop the ends thereof into like and mutuallyrepellent movable and fixed poles respectively,

and to form of the end of the other or nonassociated core-limb an opposed fixed pole at tractive of said movable pole, the bore of said coil being of suflicient width to admit of lateral oscillatory movement of the said armature therein; non-conducting and conducting limitstops for the said armature corresponding to its normal and operated positions respectively; a conducting spring extension for said armature adapted to move therewith be tween said stops, and constituting a complementary contact for the latter; and a counterspring for said armature tending to hold the same in its normal position with the said contacts separated, and adapted to restore it thereto on the cessation of the said energizing-current; substantially as set forth.

6. In an alternating-current relay the combination With the magnetizing or exciting coil U adapted for inclusion in a main circuit; and the parallelogrammic soft-iron core K forming a nearly-completed magnetic circuit, and constituted of limbs m and in passing respectively through and outside of said coil, united at one end and provided at the other with confronting polar ends a and b; of the soft-iron armature (Z pivoted at one end of said coil, passing through the bore thereof conjunctively with the said core-limb m, and having its free end between the polar ends a and 7) of said core; limit-stops P and Q mounted above the polar ends a and b respectively, the latter forming a contact-point for a cont-rolled circuit; the spring extension S of said armature extending between said limit-stops, and constituting the complementary contact of said controlled circuit; the heel-pin F of said armature and the counter-spring Gr therefor pressing said armature constantly toward the said polar end a and the non-conducting limit-stop P; substantially as described.

In testimony whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 19th day of August, 1903.

GREENLEAF WV. PICKARD.

Witnesses:

GEO. INILLIs PIERCE, FRANK (l. LOOKWOOD. 

